BAGHDAD (AP) -- Iraq's presidential council on Thursday approved a security pact that sets out a three-year timeframe for U.S. troops to leave, a spokesman said, the final step for the agreement to replace a U.N. mandate that expires Dec. 31.
The final legal hurdle to the deal was cleared even as Iraqis faced another round of bombings in a deadly week as insurgents try to chip away at recent security gains.
Two suicide bombers in explosives-laden trucks took aim at police stations in the former Sunni insurgent stronghold of Fallujah on Thursday, killing at least 15 people and wounding more than 100, Iraqi officials said.
Iraq's parliament signed off on the deal last week following months of tough talks between U.S. and Iraqi negotiators that at times seemed on the point of collapse. The entire process has been fraught with hardscrabble dealmaking between ethnic and sectarian groups.
The top two U.S. officials in Iraq welcomed the ratification of the security pact and a parallel agreement covering cooperation in other areas, which will take effect on Jan. 1.
The U.S. Embassy and the military "will begin immediately to implement these two agreements with our Iraqi partners," Ambassador Ryan Crocker and Gen. Ray Odierno, the top U.S. military commander in Iraq, said in a statement.
They also promised to support Iraq's request to the U.N. Security council to continue protection of Iraqi assets.
"And we look forward, under these agreements, to the continued reduction in U.S. forces and the normalization of bilateral relations as two sovereign and co-equal nations," the statement said.
Under the deal, U.S. forces will withdraw from Iraqi cities by June 30 and the entire country by Jan. 1, 2012. But the agreement includes the caveat that it should go before voters in a referendum by the end of July - when the deal will already be in effect.
That was a concession to Sunni demands and means the agreement could be rejected next year if, for example, anti-U.S. anger builds and demands for an immediate withdrawal grow. By that time, however, American troops will likely have left urban areas and will be a less intrusive presence.
President Jalal Talabani, a Kurd, and his two deputies Tariq al-Hashemi, a Sunni Arab, and Adel Abdul-Mahdi, a Shiite, signed the accord at their headquarters in Baghdad, council spokesman Nasser al-Ani told The Associated Press.
Iraq also will gain strict oversight over the nearly 150,000 American troops now on the ground, representing a step toward full sovereignty for Iraq and a shift from the sense of frustration and humiliation that many Iraqis feel at the presence of American troops on their soil for so many years.
Followers of anti-U.S. cleric Muqtada al-Sadr opposed the measure, demanding an immediate withdrawal, and the Shiite leader has called for peaceful protests against the continued presence of American forces in Iraq.
The U.S. military has warned that the security gains of the past year remain fragile.
In Fallujah, the apparently coordinated blasts struck within minutes of each other outside the concrete barriers surrounding two police stations in different sections of Fallujah.
A senior Iraqi police officer in Fallujah says a police station in the northern part of the city was leveled and several nearby houses were heavily damaged. A police station in central Fallujah was also struck, he said.
Police and hospital officials gave the casualty toll on condition of anonymity because they weren't authorized to release the information.
The U.S. military said two bombs exploded in Fallujah shortly before noon on Thursday, but it had no immediate information about casualties or other details.
Fallujah, 40 miles (65 kilometers) west of Baghdad, is in Anbar province and saw some of the fiercest fighting of the war before local Sunni tribal leaders joined forces with the Americans against al-Qaida in Iraq.
The city, which is largely sealed off by checkpoints, has been relatively peaceful in recent months but attacks have continued.
Northeast of Baghdad, a bomb left on a parked motorcycle exploded near a restaurant in Baqouba, killing three people and wounding 10, according to police at the security headquarters for the surrounding Diyala province.
In a separate development, an unmanned U.S. surveillance plane crashed on the runway at the Balad Air Base, 50 miles (80 kilometers) north of Baghdad, according to a statement by the U.S. Air Force.
It said the MQ-1 Predator assigned to the 332nd Air Expeditionary Wing crashed about 7:30 a.m. Thursday, but the extent of the damage was unknown.
Associated Press writer Bushra Juhi contributed to this report.
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